A known microscope device in the related art changes the gain of a detection element that detects light from a sample (for example, see Patent Literature 1 and Patent Literature 2). The microscope device according to Patent Literature 1 acquires images by changing the gain of a detector, and cuts and pastes an image acquired at a low gain and an image acquired at a high gain based on a certain threshold value so as to generate an image with an overall high signal-to-noise ratio. The microscope device according to Patent Literature 2 changes the offset, gain, and high voltage (HV) so as to measure the dynamic range of an output signal from a detection element, thereby automatically setting an optimal observation parameter.